Avrunin



Feb. 21, 1956 V. AVRUNIN SAFETY ELECTRIC SOCKET Filed Jan. 15, 1954 zo2e Fig. 3

IN VEN TOR. VICTOR AVRUNI N ATTORNEY United States Patent SAFETYELECTRIC SOCKET Victor Avrunin, Jamaica, N. Y. Application January 13,1954, Serial No. 403,803

Claims. (Cl. ZOO-51.09)

This invention relates to an electrical safety socket. Morespecifically, this invention relates to an'electrical socket adapted foruse with an ordinary electrical plug connected to any suitableelectrical apparatus which is to be supplied with electrical currentfrom the socket.

The socket of the present construction is adapted to supply current onlywhen the plug is fully inserted therein, but will not supply current ifthe plug is' only partially inserted in the socket. Furthermore, if anymetallic objects should be inserted-into the socket, such as a hairpinor wire, no electrical contact will be made which might cause shortcircuitsor shock the person introducing such objects in the socket.According to the present invention, the plug which is inserted in thepresent socket not only acts as a conductor, but also as a key whichoperates an internal electrical switch for making and breaking theelectrical circuit. This is accomplished by interposing between theprongs of the plug and the terminals of the socket an electrical bridgewhich operates only when the plug is fully inserted.

Further details and advantages of the invention will be apparent fromthe following specification and the accompanying drawings, wherein 4Figure 1 is a vertical sectional view showing a socket constructed inaccordance with the present invention and a plug about to be placedtherein,

Figure 2 is a view similar to Figure 1 showing the plug partiallyinserted within the socket, the prongs of the plug being fully insertedbut without making electrical contact, and I Figure 3 is a view similarto Figure 1 showing the plug fully inserted so as to complete theelectrical circuit for supplying current.

Referring to the drawings, the socket is comprised of a housingindicated by the numeral 10. The housing may be made of any suitablematerial, such as molded plastic material or other suitable dielectricmaterial, such as rubber, glass, ceramic and the like. The housing isadapted to retain therein a movable or floating block assembly,designated generally by numeral 12, which is formed of two portions 13and 14 retained together by a screw 16. The block 13 is provided withtwo suitably spaced channels 23 which are adapted to receive therein theprongs 25 of a plug 26 connected to electrical wires 27 for supplyingcurrent to any suitable electrical equipment. The blocks 13 and 14 aremade of any suitable dielectric material, such as plastic, rubber andthe like. The block 14 is provided with an interior opening 17 which ispreferably bevelled inwardly at its side portions 17a for retainingthereon a pair of resilient metal electrical contact members 22 whichare retained in place by means of screws 20. The block 14 is alsoprovided with bores or openings so as to permit the insertion of ascrewdriver or other tool therethrough for fastening the screws inproper position on block 14. The channels 23 communicate with theopening 17 so that it is possible to insert prongs 25 of plug 26therethrough as shown in Patented Feb. 21, 1956 Figure 2. If desired,blocks 13 and 14 may be integrally formed of plastic or rubber as asingle element.

The housing 10 is provided with inwardly extending shoulder portions 11for limiting the outward travel of the movable block 12 as well as forretaining the block 12 within the housing 10. A coiled spring 30normally tends to urge the block 12 against the shoulder portions 11 ofthe housing 10 as shown in Figure l.

A fixed block 35 is provided at the opposite end of the housing 10 whichis fixedly retained therein by means of screws 36 or any other suitablemeans. The fixed block 35 is provided with suitable openings forreceiving and retaining therein electrical contact elements 37. Theelectrical elements 37 are retained by screws 38 which also serve toconnect same to suitable power leads 39. The fixed block 35 is providedwith an internal cavity portion within which the electrical resilientcontact members 22 are adapted to be moved. Friction or abutment members40 are positioned within the inner surface of the cavity of the fixedblock member 35 as shown in Figure l. The friction members 40 arepreferably made of metal in order to withstand frictional Wear uponcontact thereon of the spring contact members 22. As shown in Figure 1,the spring contact members 22 are adapted to be releasably retained bythe friction members 40 so as to be out of electrical contact with thecontact members 37. If desired, fixed block 35 and housing 10 may beformed integrally of dielectric plastic material, rubber and the like.The block member 35 thus functions as an end wall for the housing 10.The housing 10 is provided with straps 9 retained by screws 8 forsecuring the housing in a suitable outlet box.

The operation of the safety plug will now be apparent from theconstruction previously described. With the plug 26 and its prongs 25fully retracted as shown in Figure l, the electrical contact elements 22will abut against the portion of friction members 40 which extend beyondwall portion 33 of fixed block 35. Upon moving the plug 26 further tothe left, to the position shown in Figure 2, the prongs 25 of the plug26 will press upon the spring electrical contact members 22 and deflectthem toward the central axis of the plug as shown in Figure 2, wherebythey will be released from engagement with the friction members 49. Uponmoving the plug 26 further toward the left, as shown in Figure 3, thespring electrical contact members 22 will then ride up the bevelled endportions 37a of the contact members 37 and attain frictional engagementtherewith in the locked position shown in Figure 3. In this position,the spring members 22 will then make electrical contact with theelectrical contact members 37 and will remain in such locked position.It will be understood that the use of the plug 26 as an actuator of thecircuit closing device per se permits greater latitude in thedimensioning of contacts within the receptacle. Thus, spring contacts 22and fixed contacts 37 may be of any width or shape to provide the mostefiective surface of contact notwithstanding the relatively shortoverlap between them, as shown in Figure 3. Although the elements 37 areshown as being aligned with channels 23, they may be either split oroffset so as not to be in direct alignment with channels 23 so that inevent a wire or other metal object should be mischievously inserted inthe channels 23, no electrical contact will be made. By similarlysplitting or offsetting the spring contact members 22 when the plug 26is fully inserted, the members 22 will make electrical contact with thefixed contacts 37 even when offset. When the plug is pulled manually tothe right the spring contact members 22 will then assume their initiallocked position again shown in Figure 1 due to the action of spring 30which will move the block assembly 12 against the housing shoulderportion 11.

The present socket construction provides means for making electricalcontact with a source of current only by fully inserting the plugtherein. Partial insertion of the prong members of a plug will notsupply electrical current so that it will not be possible to shortcircuit across the prongs of a plug which is partially inserted therein.It will also be observed that only one motion is required to connect theplug and socket. in other words, by merely inserting the plug directlyinto the socket by a straight thrust into the socket, an electricalcontact will be made. Previous constructions have been provided withcircular or rotatable doors interposed between the contact members whichhave to be actuated by one or more motions before it is possible toinsert the plug therein. in the present construction, the plug isinserted in its normal manner by a direct thrust and no othermanipulative movements are required to produce contact. Likewise, uponretraction of the plug from the present construction, there is no periodduring which both terminals of the plug are partially exposed andconducting electricity. In previous constructions, this makes for adangerous situation in which the two terminals may be crossed even whenthe face of the plug is more than a inch away from the face of thesocket. In the present construction, the electrical connection is brokenby the time face-tc-face contact between the plug and a member of thesocket is interrupted. Thus, there is no exposure of live terminalelectrical contacts. The present invention thus provides a safety socketwhich acts not only as a conductor and terminal, but also can beactivated electrically only by fully inserting a plug therein which actsas a key to operate an electrical switch, making and breaking theelectrical circuit. The entire mechanism is fully safe at all times andwill protect the operator from exposure to any electrical currentsunless the plug is fully inserted into the socket.

It is to be understood that the foregoing description of my invention isan illustrative embodiment thereof and that changes and modificaions maybe made which are intended to be included within he scope of theappended claims.

I claim:

1. An electrical safety socket construction comprising a housing, fixedelectrical contact elements supported in said housing, a movable memberretained in said housing, said movable member being provided with springelectrical contact members, said movable member also being provided withopenings for receiving the prong members of a plug, abutments in saidhousing for normally engaging said spring electrical contact members andmaintaining them out of electrical contact with the said fixedelectrical contact elements supported in said housing, said springcontact members being adapted to be sprung inwardly of said socketmember upon insertion of the prongs of the plug member therein andreleased from engagement with said abutments to bring said springcontact members into contact with the said fixed electrical contactelements in said housing for completing electrical circuit therewith.

2. An electrical safety socket construction comprising a housing, fixedelectrical contact elements supported in said housing, a movable blockmember retained in said housing, said movable block member beingprovided with spring electrical contact members, said movable blockmember also being provided with openings for receiving the prong membersof a plug, abutments in said housing for normally engaging said springelectrical contact members and maintaining them out of electricalcontact with the said fixed electrical contact elements supported insaid housing, said spring contact members being adapted to be sprunginwardly of said socket member upon insertion of the prongs of the plugmember therein and released from engagement with said abutments, saidmovable block member being adapted to be further moved inwardly of saidhousing to bring said spring contact members into contact with the saidfixed electrical contact elements in said housing for completingelectrical circuit therewith.

3. An electrical safety socket construction comprising a housing, fixedelectrical contact elements supported in said housing, a movable memberretained in said housing, a spring interposed between said housing andsaid movable member, said member being provided with spring electricalcontact members, said spring electrical contact members being normallypositioned out of electrical contact with said electrical contactelements by action of said spring, said movable member also beingprovided with openings for receiving the prong members of a plug,abutments in said housing for normally engaging said spring electricalcontact members and maintaining them out of electrical contact with thesaid fixed electrical contact elements supported in said housing, saidspring contact members being adapted to be sprung inwardly of saidsocket member upon insertion of the prongs of the plug member thereinand released from engagement with said abutments, said movable memberbeing adapted to be further moved inwardly of said housing to bring saidspring contact members into contact with the said fixed electricalcontact elements in said housing for completing electrical circuittherewith.

4. An electrical safety plug member comprising a housing, a fixed blockmember retained in one end of said housing, said fixed block memberbeing provided with channels for retaining therein a pair of fixedelectrical contact elements, said contact elements being connected to asource of suitable electrical power, said fixed block member beingprovided with an internal recess within which said electrical contactelements extend, the ends of said electrical contact members beingprovided with bevelled portions, a movable member retained in saidhousing, said housing being provided with a shoulder portion forretaining said movable member therein and limiting the outward movementthereof, said movable member being provided with extending springelectrical contact members, abutments in said housing for normallyengaging said spring electrical contact members and maintaining them outof electrical contact with the said fixed electrical contact elementssupported in said housing, said movable member being provided withchannel portions for receiving therein the prong members of a plug, saidspring electrical contact members being adapted to be bent inwardlytoward the axis of said plug member upon engagement of same by the prongmembers of said plug for release from engagement with said abutments, aspring member interposed between said fixed block member and movablemember for normally urging said movable member against the said shoulderportion of said housing, said spring contact members being adapted to beretained in engagement with said abutments when said block is positionedon said shoulder portion of said housing, said spring contact membersbeing adapted to be engaged in electrical contact relation to the fixedcontact members retained in said fixed block member for supplyingcurrent to said spring electrical contact members when said movableblock member is moved fully inwardly of said housing by said plugmember.

5. An electrical safety plug member comprising a housing, an end wallclosing in one end of said housing, said end wall being provided withchannels for retaining therein a pair of fixed electrical contactelements, said contact elements being connected to a source of suitableelectrical power, said housing being provided with an internal chamberwithin which said electrical contact elements extend, the ends of saidelectrical contact members being provided with bevelled portions, amovable block member retained in said housing, said housing beingprovided with a shoulder portion for retaining said movable block membertherein and limiting the outward move ment thereof, said movable blockmember being provided with extending spring electrical contact members,said movable block member being provided with channel portions forreceiving therein the prong members of a plug,

yawnabutments in said housing for normally engaging said springelectrical contact members and maintaining them out of electricalcontact with the said fixed electrical contact elements supported insaid housing, said spring electrical contact members being adapted to bebent inwardly toward the axis of said plug member upon engagement ofsame by the prong members of said plug for release from engagement withsaid abutments, a spring member interposed between said end wall andmovable member for normally urging said movable block member against thesaid shoulder portion of said housing, said spring contact members beingadapted to be retained in engagement with said abutments when said blockis positioned member.

References Cited in the file of this patent UNITED STATES PATENTS1,141,686 Jones a- June 1, 1915 2,224,366 Johnston Dec. 10, 19402,393,616 Reamer et al. Jan. 29, 1946

